Loop grippers for tufting machines are known from the prior art in various designs. The loop gripper according to U.S. Pat. No. 3,084,645 has a gripper body with a gripper finger which extends in an extension direction from a retained end to a free end. On the underside of the gripper finger, there is a cutting region which cooperates with a cutting blade. Yarn loops which are located in the cutting region can be cut by the cutting blade to produce cut pile. Also attached to the gripper body is a spring clip which cooperates with the free end of the gripper finger and in a rest position bears against a side surface of the gripper finger. Formed between the spring clip and the side surface is a gap, into which the needle or one leg of the needle can engage when the gripper finger grips a yarn loop. The yarn loop can be cut by means of the cutting blade, or alternatively, in order to produce a loop pile, can be drawn off from the gripper finger without being cut.
Another loop gripper is described in U.S. Pat. No. 4,134,347. In contrast to U.S. Pat. No. 3,084,645, the gripper finger has at its free end a protrusion which protrudes transversely away from the edge provided in the cutting region. This prevents yarn loops from being able to be drawn off from the cutting region. By way of a pivotable closing element which collaborates with the protrusion at the free end of the gripper finger, the ingress of yarn loops into the cutting region can be prevented so that, instead of cut pile, it is also possible to produce loop pile if the yarn loops are gripped by the free end of the gripper finger without being able to enter the cutting region.
In the loop gripper known from U.S. Pat. No. 4,353,317, two gripper fingers are provided, each having a cutting region, wherein the lower gripper finger is assigned a closing element which collaborates with a protrusion at the free end of the gripper finger in order to prevent yarn loops from entering the cutting region. A shorter pile is produced when the closing element is in the closed position, and a longer pile is produced when the closing element is open.
U.S. Pat. No. 2,982,239 describes a loop gripper having a straight gripper finger, which has a cutting region, and a hook-shaped further gripper finger, said gripper fingers being pivotable relative to one another. Depending on the pivoting position, the hook-shaped gripper finger can cause the loops held on the straight gripper finger to be retained for cutting purposes (cut pile production) or can unblock the cutting region of the straight gripper finger (loop pile production).